1. Field of the Invention
The present invention relates generally to an apparatus for supplying an electric power to a rotary member and a brush belt for use with the same, and more particularly to an apparatus for supplying an electric power to a rotary member such as an electromagnetic clutch or an alternator and a brush belt used for the rotary member.
2. Description of the Related Art
One of the rotary member is for instance an electromagnetic clutch. In the case of automobile air conditioners, the power is derived via the electromagnetic clutch from an engine. The major electromagnetic clutches being presently manufactured are of a so-called fixed coil type in which a gap is defined between the fixed coil and the rotor part, by way of which rotor there is attracted an armature generating a rotational force (torque). Some electromagnetic clutches are of a coil-rotation type in which the coil itself is rotated with the power from the engine.
However, no matter whether such an electromagnetic clutch is of the fixed coil type or the coil-rotation type, it generally employs a slip ring brush system as the method of supplying an electric power to the electromagnetic coil. Therefore, some manners of abutment of the brush against the slip ring may result in an insufficient electric capacity or in the breakage of the tip of the brush. The former would occur if the tip of the brush could not abut in parallel against the overall surface of the slip ring. The latter would take place if the tip of the brush abutted obliquely against the surface of the slip ring. Furthermore, some strengths of the abutment of the brush tip against the surface of the slip ring may result in early wear of the brush tip, resulting in the deposit of brush wear dusts. In particular, in case of a high-speed rotation of the electromagnetic coil, the electric power receiving part may be subjected to the early wear. Also, the coil rotation type slip ring system has not yet been prevailing since it is affected by the variations in the number of rotations of the engine, vibrations, temperatures, dusts, oils and droplets.
In view of such circumstances, there was proposed a tubular member (roller) which is rotatably mounted on a shaft provided on the end of the rotary member at its rotational center, the tubular member having an electric power supply part removably attached thereto (see Japanese Patent Pub. No. sho63-30530).
Although such means using the above tubular member can deal with such circumstances no matter whether they employ the fixed coil type or the coil-rotation type, it would be troublesome to carry out them due to too large a number of constituent parts as well as to a higher processing accuracy required. It is thus desired to somewhat simplify them with respect to the structure, operation and costs.